Had a good night on the flowbench(edited version)

Killer6 said
I'm not sure what You mean.........a Serdi(or similar equip) will cut whatever cutter you place on the tool bit holder, 1 angle to a full radius w/a seat in the middle.

Sorry, a Serdi is a brand name of a machine that cuts the valve seat, entrance, and exit with a special carbide bit. It is a machining process and not a grinding process like the 30-45-60° procedure that was described earlier. The shop that did my heads said jokingly that they don't grind seats with a rock. (grindstone). Instead of sharp angles with a stone you get smooth radius' with a Serdi. A dyno comparison would be interesting and may be just a few cfm difference.